Sketch map of the principal outcrops of the main stratigraphical units in the British Isles. The pre-Devonian formations, both sedimentary and crystalline, comprise the Precambrian and the three Lower Palaeozoic Systems. The Devonian rocks include both marine and continental (Old Red Sandstone). The Cenozoic, or Tertiary, sedimentary formations are those of the Hampshire Basin, the London Basin and East Anglia. The flood basalts of the North-west Tertiary Igneous Province are marked, but the many intrusive igneous rocks and various older volcanics are omitted for the purposes of this discussion.

A possible scenario of the evolution of the British Isles. (A) Fusion of the continental crustal blocks Laurentia, Avalonia and Baltica in the early to middle Palaeozoic cycle of events. (B) Evolution of middle to late Palaeozoic basins and orogenic uplifts. (C) Mesozoic basin and upland developments. (D) Late Mesozoic–Cenozoic (Alpine) cycle – Atlantic rifting.

A phylogenetic scheme of chordates within the stratigraphical record (after Blieck, 1992). The two known cephalochordates of the Cambrian are Pikaia gracilis from the Middle Cambrian Burgess Shale of Canada and Yunnanozoon lividum from a Chinese Early Cambrian fauna (c. 525 Ma). Thelodonts, as yet undescribed, are known from the Ordovician. Acquisition of vertebrate characters: (1) chordate features (mesoderm, notochord, etc.); (2) somitic characters (somites, creatine phosphate, etc.); (3) craniate features (neural crest, cartilaginous endoskeleton); (4) two semicircular canals, dermal ossification, etc. (5) aspidin present; (6) same four-layered structure of dermal bone; (7) paired fins, etc.; (8) gill openings in a slanted line; (9) cellular dermal bone, perichondral bone etc.; (10) heterocercal tail with change of scale ornamentation at caudal peduncle, pectoral fins, concentrated at base, etc. For full discussion see Blieck (1992), also Chen et al. (1995). The Australian group the pituriaspids, the most recently discovered and puzzling, seems to be related to the basic stock from which also came the Chinese galeaspids and the Euramerican osteostracans (see Long, 1995).

Classification of fishes and amphibians (living = †; paraphyletic exceptions = *).

A geological history of fishes. The geological periods and the ages of the period boundaries are given at the top. The shaded areas suggest the relative abundance of species within the different classes during each period (after Ommaney, 1963, with data from Benton, 1993).

The Agnatha; fishes lacking jaws. (A) Anglaspis, a heterostracan from the Siluro-Devonian; (B) Pteraspis a heterostracan from the Early Devonian; (C) Hemicyclaspis, an osteostracan from the Late Silurian; (D) Psammolepis, a Late Devonian heterostracan; (E)–(G) Silurian thelodonts, Thelodus, Phlebodus and an unnamed form from Canada; (H) the Devonian anaspid Pharyngolepis; (I) a living lamprey ammocoete larva; (J) an adult living lamprey; (K) the extant adult hagfish. Not shown are the Chinese galeaspid and Australian pituriaspid. All are approximately a third natural size.

Gnathostomata or jaw-bearing fishes. (A) an acanthodian, Parexus, at × 0.5; (B) the antiarch Remigolepis, at × 0.3; (C) the arthrodire Coccosteus, at × 0.3; (D) and (E) fish with bony skeletons: (D) a primitive actinopterygian, at × 0.5; (E) a sarcopterygian, at × 0.1; (F) fish with a cartilaginous skeleton, a hybodont shark, at × 0.1.

Age ranges of Palaeozoic fishes (after Long, 1993).

Cladograms showing the postulated relationships of the main groups of fishes (after Benton, 1993). (A) The Chondrichthyan fishes. Chondrichthyes = cartilaginous endoskeleton with exoskeleton of small scales, sometimes enlarged into head spines or fin spines. Elasmobranchi = a predaceous group with distinctive jaw suspension and quickly replaced characteristic tooth structure; no operculum, gill slits opening directly to the outside. Neoselachii = modern sharks, skates and rays; characteristic vertebrate and fin structures. (B) The major groups of Osteichthyan (bony) fishes. Actinopterygii = ray-finned fishes; Neopterygii = actinopterygians with distinctive separation of cheek and jaw bones from the opercular. Teleosti = advanced bony fishes. Elopocephala = advanced teleosts. Clupeocephala = a group derived from the Elopocephala. Euteleostei = most are characterized by acellular bone and by features of the skull and caudal skeleton. Neoteleostei = most characterized by stiff fin spines and modifications of the positions of the pectoral and pelvic fins and body proportions. Acanthomorpha = spiny teleosts with modifications for swimming concentrated in the caudal fin. Acanthopterygii = further modifications to the bones around the mouth and caudal vertebrae and fin are found in this group.

Fossilization under most circumstances preserved only a very small percentage of the living world in the fossil record. Most of the animals and virtually all the plants that lived alongside these sharks were not fossilized (after Beerbower, 1960).

Under rare conditions exceptional preservation of articulated skeletons and even so-called soft parts occurs. This diagram shows the factors involved in the preservation of a large Eocene biota in a German lake deposit. Many of these factors and pathways played a part in the preservation of complete fishes in the British Middle Devonian, Carboniferous and Jurassic record (after Franzen, 1985).

The basic channels for the flow of materials through a typical ecosystem. This is elaborated in Figure 1.12 to show the trophic flow in a late Devonian assemblage.

A model of the possible trophic flow and connections in the well-preserved Eusthenodon assemblage in the Late Devonian of the Tula region of Russia (after Lebedev, 1992). This vertebrate community included chondrichthyes, antiarchs, dipnoi and crossopterygians as well as the tetrapod Tulerpeton.

The procedures in stratigraphy and the categories within it (after Holland, 1978). Chronostratigraphy is the central repository for the data derived from the procedures and the phenomena indicated around them. The terms shown in brackets are not often used, but, logically, could be employed to greater extent.

The global stratigraphical column, based on that of the International Union of Geological Sciences (Cowie and Bassett, 1989). In the situation where alternative series and stage names are given, the left hand column is usually favoured. The geochronometric dates are based upon published isotope analyses.

Locality map showing the distribution of the 97 fossil fish sites described in this volume. They are principally grouped upon the ancient sediment-ary basins: Caledonian and Orcadian (Devonian), Midland Valley of Scotland (Carboniferous), Anglo-Welsh (Devonian), Oxford–Wessex (Triassic–Jurassic) and the Hampshire and London Basins (Cenozoic). See Table 1.2 for key to numbers.

Silurian outcrops in Britain.

Early Wenlock palaeogeography of Scotland (after Bassett, 1992).

Location map of the Lower Palaeozoic inliers of the Midland Valley, showing GCR sites 1–6.

Silurian successions in the inliers of the Midland Valley (after Cameron and Stephenson, 1984).

The five basic types of thelodont scales, lateral and basal views and sagittal section to show the typical structure: b, base; cr, non-growing crown. The thelodont Lanarkia bears large spine-like scales as well as small rotund denticles in regular rows (after Turner, 1973).

Thelodont ranges in the Silurian and Devonian of western Europe (after Janvier and Blieck, 1993).

Silurian biozones now of use in international correlation. The vertebrates are largely microvertebrate (e.g. scales of thelodonts and acanthodians) taxa (from Märss, 1986).

The Silurian succession in the Lesmahagow inlier (from Ritchie, 1985). Three vertebrate– arthropod faunal assemblages are distinguished: the Jamoytius horizon (lowest), the Ceratiocaris Beds in the Kip Burn Formation, and the (latest) fish beds in the Dippal Burn and Slot Burn Formations. Ainiktozoon is known only from the Jamoytius horizon.

(A) a reconstruction of Jamoytius kerwoodi White by Ritchie (1968); (B) anterior end of a specimen from Logan Water with poorly preserved trunk scales; (C) anterior end of specimen with no trunk scales visible; (D) part of trunk of J. kerwoodi showing somites × 1.5 (GLAHM 101382), Birk Knowes, Upper Llandovery, photographed under water (Photo: courtesy of the Hunterian Museum, Glasgow).

The thelodont Loganellia scotica (Traquair); (A) Traquair's original reconstruction in dorsal view (from Miles, 1971); (B) Turner's (1970) reconstruction in lateral view; (C) Janvier's (1996) representations of Turinia.

(A) Birkenia elegans Traquair. Well-preserved specimen from the ?Wenlockian of Birkenhead Burn, Shanks Castle, photographed under water, × 2, GLAHM V 8384 (Photo: courtesy of the Hunterian Museum, Glasgow). (B) Birkenia elegans Traquair. A restoration of this anaspid, the original fossil being c. 10 cms long (after Stetson, 1927).

Map of the geology in the vicinity of Shiel Burn (after Rolfe, 1961).

Stratigraphical sections in the Hagshaw Hills Silurian inlier to show the Fish Bed Formation (after Rolfe, 1961). The Greek letters refer to six divisions distinguished by Rolfe (1961).

(A) The thelodont Thelodus scoticus (GLAHM V8304), ?Upper Llandovery at Birk Knowes, c. × 1 (Photo: courtesy of the Hunterian Museum, Glasgow). (B) The thelodont Lanarkia horrida (GLAHM V2302), ?Wenlock at Seggholm, ?Slot Burn; at about natural size (Photo: courtesy of the Hunterian Museum, Glasgow).

(A) The anaspid Lasanius problematicus Traquair. Specimen from an unidentified horizon, Segholm (Slot Burn), c. × 2, GLAHM V 2286 (Photo: courtesy of the Hunterian Museum, Glasgow). (B) The anaspid Lasanius problematicus Traquair. Restoration in lateral view and possible feeding and swimming positions as suggested by Parrington (1958).

Ateleaspis tessellata Traquair. (A) Reconstruction in lateral view, c. × 0.3; and of the headshield and front part of the trunk; (B) in dorsal and (C) ventral view, c. × 0.5, (after Ritchie, 1967): cmm, transverse sensory canals; D1 and D2 anterior and posterior dorsal fins; dsf, dorsal sensory field; ifc, infra-orbital sensory canal; lc, lateral sensory canal; lsf, lateral sensory field; o, orbit; pec, left pectoral fin; vlr, ventro-lateral ridge; vrs, ventro-lateral scales.

Geological sketch-map of the coast to the north of Stonehaven (after McGregor, 1978); The Toutties is the area of foreshore south of Cowie Harbour.

Stratigraphical log of the uppermost part of the Downtonian at The Toutties (after MacGregor, 1968).

The ventral disc of Traquairaspis campbelli (Traquair) (holotype, RSM) from the Cowie Harbour Fish Bed, × 1.3. It has the characteristic serrated tubercles now known in related heterostraci throughout the circum-Arctic Siluro-Devonian and may be one of the oldest traquairaspidiforms (from Kiaer, 1932b).

Mesacanthus mitchelli (Egerton) restoration in lateral view, approximately natural size (after Watson, 1937): isp, intermediate spine; with details of squamation of specimen from Tillywhandland (from Young, 1995).

Map of the Downtown Series throughout the Welsh Borders, with schematic summaries of the stratigraphical successions and relationships with the Ludlow Series: UWF, Upper Whitcliffe Formation; DCSF, Downton Castle Sandstone Formation; LBBM, Ludlow Bone Bed Member; PSM, Platyschisma Shale Member; TSF, Temeside Shale Member; LF, Ledbury Formation; PPB, phosphatized pebble beds; PHF, Platyschisma helicites Formation; YDF, Yellow Downton Formation; GDF, Green Downton Formation; RDF, Red Downton Formation; Lud, undifferentiated Ludlow strata; SM, Sandstone Member; TF, Tilestones Formation; u/c, unconformity (after Bassett, Lawson and White, 1982).

Correlation table of Late Silurian–Lower Devonian formations of the Anglo-Welsh province (after Siveter et al., 1984; House et al., 1977).

PÍ ídolí (latest Silurian) palaeogeography of southern Britain (after Bassett et al., 1992). (A) early PÍ ídolí; (B) late PÍ ídolí.

Silurian thelodont denticles from the Welsh Borderland (after Turner, 1973). (A) from the T. pococki zone of the Downtonian: a, b, Goniporus alatus (Gross), c, d, Loganellia ludoviensis (Gross); e, Loanellia cuneata (Gross); f, L. cruciformis; g, Turinia pagei (Powrie); h, Loganellia sp. indet. (B) (Lower) Downton Formation, a, Thelodus costatus, Pander; b, Kataporodus tricavus Gross; c, Goniporus alatus (Gross): (C) Woolhope Limestone, a–b, Thelodus parvidens Agassiz; c–d–e, Loganellia ludoviensis (Gross).

Late Silurian heterostracan vertebrates from the Welsh Borders area. (A) Anglaspis macculloughi in dorsal and lateral views, × 0.75, and, Tesseraspis tessellata in dorsal view, × 0.35; (B) restorations of the carapace of Traquairaspis pococki showing the ornamentation of the dorsal and ventral discs, and of the ventral disc of T. symondsi, dorsal view; (C) Traquairaspis symondsi restorations of the carapace in dorsal and ventral views (after Tarrant, 1991); (D) Tesseraspis tessellata part of dorsal carapace, × 0.35 (after Halstead Tarlo, 1964).

Stratigraphical distribution of the Siluro-Devonian agnathans of the Old Red Sandstone continent (England and Wales; after Janvier and Blieck, 1993).

Geological sketch map and stratigraphical section of the Cwar Glas site in the Sawdde Gorge (after Bassett, 1982).

(L) Dorsal and (R) ventral discs of the cyathaspidid Archaegonaspis ludensis from the Ludlovian, × 0.8 (from Lankester, 1864).

Sketch map and stratigraphical section of the site at Ludford Lane, Ludlow (after Bassett et al., 1982).

Fossils from the Ludlow Bone Bed illustrated in a plate from Murchison's Siluria (1872). 1–8, Plectrodus mirabilis, fragments of jaws; 9–12, P. pustuliferus, fragments of jaws; 13, 14, Onchus murchisoni, fin spines; 15–17, O. trenuistriatus, fin spines; 18, Thelodus parvidens, denticles; 19–20, indeterminable fragments; 21–28, coprolites containing invertebrarte fragments; 29, Orthis lunata Sowerby; 30, Pachtheca sphaerica. All approximately natural size.

Thelodonts from the Ludlow Bone Bed (after Turner 1973). (A) Thedolus parvidens; (B) Thelodus bicostatus; (C) Loganellia ludlowiensis head scale; (D) Thedolus pugniformis; (E) Thelodus parvidens?; (F) Thelodus trilobatus.

Ludlow–PÍídolí correlation for Europe and North America. Vertical columns not drawn to scale (after Siveter et al., 1989).

Section at Ledbury railway cutting recorded by Symonds (1860). Even more than 100 years later much of this section was still visible; recently, however, much of the western end has become obscured.

Osteostracans from the Ledbury cutting. (A) Hemicyclaspis murchisoni Egerton in rare preservation, one of many such slabs collected over 100 years ago, c. × 0.25, (photograph courtesy The Natural History Museum,London, T05398/A). (B) Restoration of vertebrates found at Ledbury: a, Hemicyclaspis murchisoni; b, Auchenaspis egertoni Lankester; c, Didymaspis grindrodi Lankester (from Blieck and Janvier, in press).

Hemicyclaspis murchisoni Lankester, detail of the dorsal surface of the headshield: p, pineal foramen; o, orbits; nh, nasal hypophysis; lsf, lateral sensory field; msf, median sensory field (after Stensiö, 1932).

Stratigraphical section at Temeside. (After Elles and Slater, 1906).

Sketch map of the GCR site at Tite's Point, and stratigraphical section (after Cave and White, 1971).

Cyathaspis banksi Lankester, × 1.25; a primitive heterostracan, relatively common in Ludlow–PÍ ídolí sites in this region. (A) external surface of ventral disc; (B) internal surface of the ventral disc; (C) cast of the internal surface of dorsal disc; (D) impression of the internal surface of the dorsal disc showing position of the gill pouches (g), semi-circular canals (c), orbits (o) and pineal foramen (p). Specimens from Kington, in the Museum of Practical Geology when figured by Lankester (1868).

Sketch map and section of the outcrop at the cliffs and foreshore at Lydney (after Allen, 1978).

Vertebrate fragments from Lydney. (A) Tesseraspis tessellata Wills, tesserae scattered at many horizons; (B) Sabrinacanthus: (B'), (B") details of ornamentation; al, ascending lamina; ispl first intermediate spine; psp, pectoral spine; ppsp2, 3, paired pectoral spines; sc, scapula. (B) after Miles (1973).

Sclerodus pustuliferus, cephalic shield in dorsal view; apit, anterior pit; cf, central field; dsf, dorsal sensory field; lsf, lateral sensory field; mf, marginal foramen; mpit, median pit; no, nasal opening; o, orbit; po, pineal opening; ppit, posterior pit; approximately natural size (after Forey, 1987, © The Natural History Museum, London).

The stratigraphical section at Tin Mill Race (after Elles and Slater, 1906).

The Old Red Sandstone Continent (Euramerica or Laurussia); a general map, early Devonian to mid-Devonian times.

Stratigraphical sections of the Devonian in the Welsh Borderland–South-west England (after House et al., 1977) with GCR site horizons indicated: A, Afon y Waen; B, Besom Farm; BS, Bedruthan Steps; C, Cwm Mill; D, Devil's Hole; H, Heol Senni; M, Mill Rock; O, Oak Dingle; P, Portishead; PC, Prescott Corner; W, Wayne Herbert. Exact stratigraphical positions are not certain.

The Silurian–Devonian succession in the Welsh Borders with faunas and suggested environments (after Allen and Tarlo, 1963).

Fish zones in the Upper Downtonian and Dittonian of the Welsh Borderland and in the Lievin Group in northern France (after Blieck and Janvier, 1989). N.B. a narrow zone of Pteraspis rostrata between those of Rh. crouchi and Protopteraspis is postulated for northern France and may also be justified in Britain.

The sites and stratigraphical distribution of some pteraspidid species in the Welsh Borderland (after Blieck, 1985, with data from Ball and Dineley, 1961). Pteraspidid biozones within the Lower Devonian of the Welsh Borderland. Localities yielding zonal species (mostly akin to Pteraspis rostrata): principal map area: 1, Cradley, near Malvern; 3, Guildings Brook, Trimpley; 4, Wayne Herbert Quarry; 12, Pool Quarry, Walterstone; 14, Goldstop, Newport; 15, Kentchurch Hill, Hereford; 16, Castle Mattock; 17, Pandy, Monmouth; 18, Wern Gwenny, Dorstone; 20, Hopton Brook, Cleobury Mortimer; 22, Hazely Brook West, Cleobury; inset (Brown Clee Hill area): 2, Whitbatch Quarry, Ludlow; 5, Ledwyche Brook, Ludlow; 6, Targrove Quarry, Ludlow; 7, Oak Dingle, Bouldon; 8, Abdon Brook; 9, Targrove; 10, New Buildings, Holdgate; 11, Rea Bridge, Derrington; 13, Jubilee Brook, Hopton Cangeford; 21, Upton Cressett Quarry. Protopteraspis occurs at: 23, Meadowley Bank, Morville; 24, Monkhopton; 25, The Leath; 26, New Inn; 27, Besom Farm. Rhinopteraspis occurs at: 28, Rea Brook, Silvington; 29, Primrose Hill Quarry; 30, Wilderness Quarry, Mitcheldean; 31, Hoel Senni.

Map of the Lower and Upper Old Red Sandstone divisions in the Anglo-Welsh Basin with GCR sites indicated. Key to numbers is provided in Table 1.2.

Modes of occurrence of vertebrates in the Old Red Sandstone (after Dineley and Loeffler, in press). (A) separate, perhaps different, communities within a fluvial basin yield materials that are swept together and mixed downstream; (B) deposition within a meandering river system where vertebrate remains accumulate in a variety of situations. (C) vertebrate remains commonly occur within intraclast conglomeratic layers overlying erosion surfaces cut in siltstones or sandstones.

Stratigraphical section in The Devil's Hole (after M.A. Rowlands, MS). The base of the Main 'Psammosteus' Limestone is mapped as the base of the Ditton Group, which has predominantly pteraspidid faunas.

Traquairaspis (Phialaspis) symondsi (Lankester), restorations of the carapace on the basis of material from Devil's Hole by P.R. Tarrant (1991). (A) carapace in dorsal view, showing ornamentation of tubercles and branchial openings set near the middle of the dorsal surface of the branchial plates; (B) the sensory canal pattern of the dorsal carapace; (C) the carapace in ventral view with characteristic smooth central area; (D) pattern of sensory canals on the ventral side of the carapace; (E) and (F) lateral view of the carapace with sensory canals shown: alp, anterior lateral plate; bcp, branchio-cornual plate; bro, branchial opening; dd, dorsal disc; vd, ventral disc; lp, lateral place; mop, median oral plate; or, orbit; orp, orbital plate; pi, pineal opening; pip, pineal plate; ro, rostrum; sca, smooth central area; dv, dorsal vane (or spine).

Protopteraspis gosseleti Leriche. White's (1950b) Pteraspis (Simopteraspis) leathensis (A)–(C), is now regarded as a junior synonym of this species (D). The lateral line canals are shown by broken lines in C and D. (A)–(B) from White (1950b); (C), (D) from Blieck (1985).

Section through the cyclothem in the Lower Ditton Group at Oak Dingle, Tugord (after Allen, 1964, and M.A. Rowlands MS).

Pteraspis rostrata var. trimpleyensis White, common fragments occur in Oak Dingle, Bouldon, and the adjacent Bouldon ford. This specimen from Bouldon figured by White (1961).

The succession at Cwm Mill, Abergavenny (after Allen, 1964).

Cephalaspids from Cwm Mill (after White and Toombs, 1983). (A) Cephalaspis cradleyensis Stensiö, restoration of headshield; (B) Cephalaspis cwmmillensis White, holotype in dorsal impression and counterpart, with restoration: nsf, nerve canals to lateral sensory field; rv, rostral vein; sof, supra-oral field; (C) Cephalaspis abergavenniensis White, external dorsal aspect of the headshield and part of the thorax with counterpart and restoration; (D) Cwmaspis (Cephalaspis) billcrofti White, part of headshield in dorsal aspect, with restoration (after White, 1963).

Rhinopteraspis crouchi (Lankester) from Cwm Mill (after White, 1973; Blieck, 1980). (A) R. crouchi carapace in dorsal view with sensory canal system shown by broken lines: b, branchial openings; o, orbits; (B) R. dunensis (Roemer) carapace in dorsal view, the extreme elongated form found in the higher Dittonian strata: (C), (D) dorsal discs; (E), (F) rostral plates.

Pteraspids from Wayne Herbert Quarry, after White (1935). (A) Pteraspis rostrata var. toombsi, dorsal view of the carapace with parts of the lateral line system shown; (B), (C) ventral views of the rostrum and oral appratus, NHM P17488 × 0.4 and NHM P17487 × 1; (D) Pteraspis waynensis (P 16524) × 0.5, outline of the ventral disc with lateral line canals indicated; (E) Pteraspis rostrata var. toombsi (P16789) × 0.33, almost complete individual preserved as an external mould, ventral view of carapace trunk and tail; (F) the same specimen preserved in counterpart, × 0.33, seen in dorsal view; (G) Pteraspis jackana (P17628) × 0.5 approximately, dorsal disc with traces of lateral line canals in dorsal view; (H)–(J) Pteraspis rostrata var. toombsi, external lateral impressions of tails with squamation (NHM P 17488, NHM P17521, NHM P 17477), at c.× 0.25.

(A) Poraspis sericea Lankester from Wayne Herbert Quarry: a dorsal aspect of the dorsal disc of the holotype (NHM P.4117); (B) median dorsal, lateral, ventro-lateral and median ventral scales of Poraspis; (C) lateral profile of the dorsal disc of Poraspis; Br, position of the branchial opening between margins on the disc and the branchial plate; O, position of the orbit; R, rostrum; (D) Nikolivia milesi, denticles from the trunk showing overlap (NHM P. 53902). (From Turner, 1982a).

Acanthodians from Wayne Herbert Quarry (after Miles, 1973; Young, 1995). (A) Ptomacanthus anglicus Miles × 0.25; (B) Vernicomacanthus waynensis Miles, × 0.45; (C) Uraniacanthus spinosus Miles, × 0.66, with detail (× 2) of scale type in vicinity of the pectoral spine.

Section in the old quarry at Besom Farm, Wheathill (after M.A. Rowlands MS).

Restorations by Blieck and Janvier (1989) of vertebrates occurring in the Lower Devonian at Artois, France. The same species (A, B, C, D, E) and Pattenaspis occur in South Wales and the Welsh Borderland. (A) Turinia pagei (Powrie); (B) Rhinopteraspis crouchi (Lankester); (C) Kujdanowiaspis sp.; (D) Pattenaspis artesensis (Agassiz); (E) Protaspis (Europrotaspis) cremulata White, the holotype (NHM P28801) an imperfect dorsal shield c. × 0.66. br, Branchial plate; bro, branchial opening; brd, branchial duct; coc, cornual contact surface on branchial plate; cop, cornual plate; do, dorsal disc; or, orbital plate; ora, orbit; ro, rostrum; sp, shells of spirorbis attached to undersurface of dorsal disc (after White, 1961).

Althaspis senniensis: (A) rostral plate from Hoel Senni Quarry; (B) a ventral disc from Hoel Senni Quarry (after Loeffler and Thomas, 1980), both approximately natural size.

Palaeogeography of the Early Devonian in northern Britain (after Bluck et al., 1992). (A) palaeogeography of Lochkovian time, c. 408 Ma; (B) palaeogeography of Late Pragian–Emsian time, c. 400 Ma. Continuing movement of the fault-bounded blocks dominated the area of Scotland throughout this interval, with uplift continuing to the north and south of the Midland Valley.

Lateral variation in the Lower Devonian strata of the Strathmore Syncline in the northeast of the Midland Valley of Scotland (after Armstrong and Paterson, 1970).

Cephalaspis lyelli Agassiz. (A), (B) Dorsal and (C) lateral views of the headshield and trunk region of the lectotype (NHM P 20087) from Glamis, Angus (after White, 1958b): lsf, lateral sensory field; msf, median sensory field; n, nasal hypophysis; o, orbit; p, pineal; pa, pectoral appendage.

Cephalaspids from the Early Devonian of Scotland (from Stensiö, 1932, © The Natural History Museum, London). (A) Cephalaspis powriei Lankester headshield in dorsal view after specimen RSM 138, × 0.8; (B) C. spinifer headshield after the holotype RSM 1891.92.149, × 0.8; (C) C. spinifer complete animal in dorsal view, × 0.7.

New restorations of Scottish Early Devonian thelodonts by Turner (1992): (A) Turinia pagei (Powrie); (B) Lanarkia spinosa Traquair; (C) Loganellia scotica (Traquair), in which post-pectoral fin and tail are hypothetical. All are c. × 0.75.

Restorations of acanthodians from the Early Devonian of Scotland. (A) Mesacanthus mitchelli (Egerton), × 2.0; (B), (C) Euthacanthus macnicoli Powrie × 0.8 in lateral and ventral views; (D) Ischnacanthus gracilis (Egerton), × 1.25 approx.; (E) Mesacanthus sp. approximately natural size (taken with permission from J. Long, 1995); (F) Parexus sp., approximately natural size. From various sources.

(A) Tillywhandland Quarry: the succession (after Trewin and Davidson, 1996). (B) Tillywhandland Quarry: the recorded positions of the fauna and flora within the fish bed (after Trewin and Davidson, 1996).

Characteristic acanthodian scales from Tillywhandland Quarry. (A) Ischnacanthus gracilis (Egerton), NHM P 62266, scales rhombic, sub-rhombic or polygonal, relatively flat to gently convex and smooth; (B) Mesacanthus mitchelli (Egerton), P 140 and 10892, scales smooth with flat crowns, sharp posterior point; (C) Euthacanthus macnicoli Powrie, scales with simple ribs, very flat crowns with five to ten well-spaced grooves. (Courtesy V.T. Young.)

A restoration of the margins of ‘Lake Forfar’ as proposed by Trewin and Davidson (1996). A vagrant benthos of cephalaspids, eurypterids and other invertebrates occupied the shallows; acanthodians lived in the open waters. Bottom conditions were probably oxygen-poor. Terrestrial arthropods inhabited the vegetated land adjacent to the lake. From nearby volcanoes quantities of fine ash periodically drifted over the lake, while there was throughout a seasonally variable input of fine fluvial sediment.

Aberlemno Quarry, stratigraphical section (after Armstrong, 1978).

Cephalaspids from Wolf’s Hole Quarry. (A) Cephalaspis scotica White, imperfect headshield is dorsal aspect, holotype RSM Powrie collection 1981.92.135, × 2. (B) Securiaspis waterstoni White, imperfect headshield in dorsal aspect, holotype, Perth Museum, unregistered, × 1. (C) Securiaspis caledonica White, external impression of headshield. Area to left of dotted line is restored. Perth Museum, unregistered, slightly less than natural size. (From White, 1963)

Pteraspis mitchelli Powrie from Wolf's Hole Quarry. (A), (B) Negative and positive counterparts of a small dorsal shield. Lectotype, Bridge of Alan, RSM Powrie Collection, 1891.92.118 and 117, × 1. (C) External impression of imperfect dorsal shield, Bridge of Alan, Perth Museum, unregistered, × 1. (D) Very imperfect dorsal shield figured by Lankester (1868), Bridge of Alan, RSM Powrie Collection, 1892.92.119, × 1. (E) External impression if imperfect dorsal shield. Specimen figured by White (1935). Bridge of Alan, NHM P 16808, × 1. (F) external impression of small dorsal shield. RSM Powrie Collection, 1892.92.122 × 1. (All figures from White, 1963.)

Palaeogeography of the Middle Devonian, 380–375 Ma, of Scotland and adjacent North Sea (after Bluck et. al., 1992).

Stratigraphical sections of the Middle Old Red Sandstone of Scotland, Orkney and Shetland, with GCR site shown.

Ranges of the common fossil fishes in the Middle Old Red Sandstone of the Orcadian Basin compared with the Eastern Baltic vertebrate biozones (largely after Donovan et al., 1974; Dineley and Loeffler, 1993; and Mark-Kurik, 1978). Z, Biozones distinguished by Donovan et al., (1974): 1, Thursius macrolepidotus; 2, Coccosteus cuspidatus; 3, Palaeospondylus gunni; 4, Dickosteus threiplandi; 5, Asmussia murchisoniana; 6, Millerosteus minor; 7, Watsonosteus fletti. A, Asterolepis; P, Psammosteus; Sch, Schizosteus

Diagrammatic reconstruction of the marginal environments around the Middle Devonian Orcadian Basin of Scotland and the North Sea at a time of high stable water level (after Trewin, 1986). The shallow-water well-oxygenated zone (A) provided a variety of habitats for the fish, which were ultimately preserved in the deeper deoxygenated zone (B).

Fossil fishes from Westerdale Quarry. (A) The lungfish Dipterus valenciennesi Agassiz (Photo: courtesy The Natural History Museum, London, T00826/A), approximately natural size. (B) D. valenciennesi in restoration by Ahlberg and Trewin (1995); (C) the osteolepid Thursius (Photo: courtesy The Natural History Museum, London, T00448/A), c. 12 cm; (D) T. macrolepidotus (Sedgwick and Murchison) (from Jarvik, 1948a).

The section of Achanarras Quarry, after Trewin (1986). Numbers 1–6 are the main fossiliferous horizons.

Achanarras Quarry (photo: D.L. Dineley).

Particularly fossiliferous horizons with well-preserved fishes may result from mass mortality events induced by planktonic blooms. The axonic conditions extend throughout the shallow marginal areas (A); following this, carcasses drift into deeper water in a bloated conditions (B); after further decay (C), they sink through the thermocline and are preserved in laminites in the anoxic hypolimnion (D). The depth of the thermocline may have been no more than a few tens of metres (after Trewin, 1986).

Common fishes at Achanarras Quarry: Pterichthyodes milleri (Miller) reconstructions in (A) dorsal, (B) ventral and (C) lateral aspects, × 0.33 approximately. (D) Palaeospondylus gunni Traquair in characteristic preservation with the head and anterior end in dorsal view but the posterior part of the vertebral column in lateral view, after Moy-Thomas (1940). (D) Photograph GLAHM V7015 showing typical compression preservation, c. × 0.8 (Photo: courtesy of Hunterian Museum, Glasgow). (F) T05399/A, with an early model of the animal, × 0.5 (Photo: courtesy The Natural History Museum, London). (G) Palaeospondylus gunni Traquair in characteristic preservation with the head and anterior end in dorsal view but the posterior part of the vertebral column in lateral view, c. × 6 (Photo: courtesy of the Hunterian Museum, Glasgow). (H) Dipterus valenciennesi Agassiz Photograph GLAMH V3656 showing the commonly well-preserved nature of this fossil lungfish, c. × 0.75 (Photo: courtesy of the Hunterian Museum, Glasgow).

Geological sketch map of GCR Site Cruaday Quarry, Mainland, Orkney, based on the Geological Survey Orkney sheet.

The Sandwick Fish Bed (after Trewin, 1976), showing division of the fish-bearing laminites into an upper and a lower leaf. Fish distribution is shown in the histograms for the upper leaf. ‘Larger acanthodians’ are mostly Mesacanthus and Cheiracanthus.

Acanthodian species from Cruaday Quarry. Restoration of Diplacanthus crassisimus Duff: (A) lateral view; (B) ventral view, approximately natural size. (C), (D) Scales of D. crassisimus, posterior to the right: (C) exterior view; (D) side view, c. × 60. (E), (F) Scales of Cheiracanthus murchisoni; (E) interior view; (F) exterior view, c. × 55 (scales from Denison, 1979). (G) ‘Rhadinacanthus’ Diplacanthus longispinus Agassiz scales with well-defined ribs and scalloped posterior margin; (H) Diplacanthus striatus Duff, scales with fine transverse grooves, (G) and (H) c. × 50 (courtesy of V.T. Young).

Osteichthyan species from Cruaday Quarry. (A)–(C) The osteolepid Osteolepis macrolepidotus (Sedgwick and Murchison), restoration in lateral, dorsal and ventral views respectively; (D) Gyroptychius agassizi Traill, restoration in lateral view. (After Jarvik, 1948a.)

The stratigraphical section in the brook at Edderton. The fish are confined to units 2, 3 and 4. (After Peach et al., 1912.)

The Edderton ptyctodont Rhamphodopsis threiplandi Watson. (A) restoration of the skeleton in lateral view; (B) restoration of the skull in lateral view; (C) restoration of pectoral girdle in ventral view (after Miles, 1967).

Correlation of the area Strathpeffer–Black Isle–Tarbat Ness, showing the central position of the Nodular Fish Beds and the Edderton Fish Beds (after Donovan, 1978).

Den of Findon section (from Trewin and Kneller, 1987).

Fishes from the Den of Findon. (A), (B) Cheirolepis trailli Agassiz, restorations of lateral and ventral views respectively (from Pearson and Westoll, 1979). (C)–(E), Coccosteus cuspidatus Agassiz: (C) restoration of the fish head in lateral view; (D) restoration of the head and trunk shields in dorsal view; (E) restoration of the skull in anterior view (after Miles and Westoll, 1968). (F) Cheirolepis trailli Agassiz, a more or less complete specimen in lateral view, T00382/A, × 0.75 (Photo: courtesy The Natural History Museum, London).

Tynet Burn, map of the GCR site and section through the fish-bearing beds.

Fossil fishes from Tynet Burn. (A) Cheriacanthus latus Egerton, a restoration based upon NHM P 15286 with scales from below and above the lateral line; (B) Cheiracanthus murchisoni Agassiz, a restoration based upon NHM P 6189 with scales from above and below the lateral line ((A) and (B) from Young, 1995); (C) T04134R of Cheiracanthus× 2 (Photo: courtesy The Natural History Museum, London); (E), (F) Reconstructions based on species from Tynet Burn: (E) skull roof with surface ornamentation and lateral line canal grooves; (F) in outline with radiation centres shown. (D) photograph GLAHM V3573, of Mesacanthus pusillus (Agassiz) × 2.5, specimens preserved in nodules.

Stratal settings of the Melby Fish Beds (after Mykura and Phemister, 1976).

Fishes from Melby: (A) dorsal view of the head and pectoral shield of the arthrodire Homosteus (after Moy-Thomas and Miles, 1971); (B) the osteichthyid Gyroptychius in dorsal and lateral view (after Jarvik, 1948a).

Stratigraphical section through Dipple Brae Fish Bed (based on data from M.A. Rowlands MS).

(A) The coccosteid arthrodire Dickosteus threiplandi Miles and Westoll; outline of the skull roof and cheek bones laid out in a single plane, based on the holotype RSM 1962.4, (after Miles and Westoll, 1963). (B) Cephalaspis magnifica Traquair, cephalic shield in ventral view at × 0.23.

Sketch map of the geology of Holborn Head, near Thurso (after Hamilton and Trewin, 1994).

Distribution and abundances of fossil fish in Holborn Head Quarry (after Hamilton and Trewin, 1988).

The arthrodire Millerosteus minor (Miller). (A) Reconstruction in lateral view of the head and thoracic region of this species from the Mey and Ackergill Beds, Thurso Flagstone Group, of Caithness and Orkney (after Desmond, 1974); md, median dorsal plate; nu, nuchal plate; x, rostrum. (B) median dorsal plate, external aspect; (B') median dorsal plate, internal aspect. (C) Nuchal plate, external aspect.

Locality map of the John o'Groats area (after Trewin and Hurst, 1993).

Sketch map of the geology of south-east Shetland, including Exnaboe and Sumburgh Head (after Mykura, 1976).

Fossil fish found at Exnaboe, Shetland. (A) Stegotrachelus finlayi Woodward and White, an early actinopterygian from Exnaboe; (B) Pentlandia macroptera Traquair, × 0.5; (C) Microbrachius dicki Traquair, reconstruction in dorsal view of the carapace of the smallest antiarch, based largely on RSM 1877.22.4 from John o’Groats and DMSW P 513 from Deerness; (D) Watsonosteus fletti (Watson) from Deerness (after Miles and Westoll, 1963); outline drawing of NHM P 11732 in dorsal view; avl, anterior ventro-lateral plate; pmv, posterior ventro-lateral plate; pvl, posterior ventro-lateral plate; r, rostrum.

The antiarch Asterolepis thule Watson from Sumburgh Head, c. × 0.2. Reconstruction after Janvier (1996).

The palaeogeography of southern England and Wales during Late Devonian time (c. 370–365 Ma), based upon outcrop and borehole evidence (after Bluck et al., 1992).

Distribution of Mid and Late Devonian outcrops and GCR sites in England and Wales (site numbers as in Table 1.2).

Simplified non-palinspastic facies section of Devon and Cornwall (after House, 1975).

Sketch map and section through the Late Devonian near Portishead (after Pick, 1964).

Fossil fishes from the Late Devonian of Woodhill Bay, near Portishead. (A) Reconstruction of the large porolepiform Holoptychius spp. (after Janvier, 1996); (B) Holoptychius scales, c. × 0.5; (C) Bothriolepis maxima Agassiz, restoration in dorsal view, c. × 0.5; (D) Asterolepis maxima Agassiz, × 0.3; (E) Glypopomus kinnairdi Woodward restoration after Jarvik.

Groenlandaspis from Portishead and other localities. Reconstruction of Groenlandaspsis (taken with permission from J. Long, 1995), length of animal c. 25 cm. (A) Dorsal view of cranial roof plates; (B) plates of the trunk armour in lateral view; (C) trunk armour in ventral view (after Ritchie, 1974), (A)–(C) × 0.5; (D) reconstruction (after Long, 1995); (E) reconstruction of Groenlandaspsis showing ventral surface, by Ritchie (1971).

Vertebrates from the Upper Old Red Sandstone at Prescott Corner and nearby, Shropshire. (A) Pseudosauripterus anglicus (Woodward) cast of the right entoperygoid, × 0.75; (B) Eusthenopteron farloviensis White, right cleithrum, Prcl, process of cleithrum, × 0.5. Specimens from Church Quarry, figures by White (1961).

Stratigraphical section in the stream at Afon Y Waen (after Hall et al., 1973).

Upper Old Red Sandstone outcrops and locations of GCR sites; O, Oxendean; HH, Hawk's Heugh; Bhl, Boghole; Sc, Scaat (Scat) Craig.

Late Devonian palaeogeography of Scotland, c. 370–365 Ma (after Bluck et al., 1992).

Upper Devonian stratigraphical successions in the Cheviot, Midland Valley and Moray Firth areas of Scotland (after Westoll, in House et al., 1977).

Stratigraphical ranges of widespread and relatively common Mid- and Late Devonian vertebrates in Euramerica (after Blieck et al., 1988). P, Phyllolepis; B, Bothriolepis; R, Remigolepis; G, Groenlandaspis; Pt, Pterichthyodes; A, Asterolepis (all × 0.25); M, Microbrachius, (× 1.0).

Sketch map of Oxendean Burn area.

The antiarch Bothriolepis hayi Miles (1968) from the Oxendean Beds of Oxendean Burn. (A) restoration of the trunk-armour in ventral aspect based on RSM 11967.34.43 and FR 1867, × 0.2; (B) restoration of the dorsal trunk armour, somewhat flattened, based on RSM 1967.34.16, × 0.2 (after Miles, 1968); (C) reconstruction of Bothriolepis (after Long, 1995), × 0.42.

Geological sketch map and section of the Hawk's Heugh (GCR site) coastline (after Greig and Davies, 1978).

The antiarch Remigolepis. (A) Restoration after Ritchie (1986); (B) the carapace in dorsal aspect (after Miles, 1968).

Sketch map of Muckle Burn–Whitemire GCR site area.

Suggested correlation of the Upper Old Red Sandstone of the Moray–Nairn area with the successions in Greenland, Spitsbergen, Belgium and the Baltic Province (after Miles, 1968; Westoll, 1977).

Scaat Craig GCR site sketch map.

Psammosteids from Scaat Craig. (A) Restored dorsal view; (B) a restoration of Psammolepis, both × 0.5 (after A. Bistrova).

(A) Holoptychius nobilissimus Agassiz, a restoration from Scaat Craig, × 0.2; (B) Holoptychius specimen from Classbinnie, Perthshire, figure in ventral aspect, × 0.3 (after Murchison, 1872).

Fossil tetrapod bone fragments from Scaat Craig (from Ahlberg, 1995). (A), (B) Elginerpeton pancheni Ahlberg, holotype RSM G 1967.17.1, in ventro-lateral and dorsal views. (C), (D) Reconstruction of the mandible in lateral and mesial views: brackets indicate parts of the jaws preserved in different specimens. (E), (F) the premaxilla, OUM Geol. Col D796, anterior part in dorsal and ventral views. (G)–(I) the posterior part of the premaxilla, NHM P9776, in lateral, ventral and dorsal views (vertical hatching = broken bone).

Maps of Carboniferous palaeogeographies: (A) Late Tournaisian; and (B) Late Viséan; and (C) Namurian.

Carboniferous stratigraphy and correlation (after MacGregor, 1960).

Carboniferous outcrops in Britain: present GCR sites are limited to the south of Scotland and to the Border country and the south-east Pennines. Horizons previously yielding fossil fish occur at Oreton (Shropshire), in the Bristol Avon gorge and the west coast of Devon. Midland Valley sites: 54, Wardie; 56, Cheese Bay; 57, Inchkeith; 58, Ardross Castle; 59, Abden. Glasgow area site: 61, Bearsden. Berwickshire sites: 53, Foulden; 55, Glencartholm. Derbyshire: 60, Steeplehouse Quarry.

Basal actinopterygian fish morphology (after Lauder and Liem, 1983). (A) Moythomasia nitida, Late Devonian, with stout body, large eyes and long jaws, dorsal ridge scales behind the dorsal fin; (B) Cheirolepis canadensis, Mid-Late Devonian, elongate with tiny scales; (C) Aduella blainvillei, Early Permian, stout body, large scales, arrow points to ‘chondrostean hinge’, large eyes, suborbital and preopercular bones in head, small mouth; (D) Andriochthys tuberculatus, Early Carboniferous, deep body, small tail and paired fins, large scales and prominent dorsal ridge scales; (E) a characteristic early actinopterygian scale bearing a small peg that articulates with the scale immediately above it.

Cladogram of the relationships of the different groups of early actinopterygians (from Gardiner and Schaeffer, 1989). It is based on a preliminary cladogram of a visual comparison of the nasal-temporal bones of the head and also upon a computer analysis of a further large data matrix.

Carboniferous chondrichthyans: (A) a cladoselachid persisting from the Late Devonian, × 0.16; (B) a symmoriid, Denea, × 0.16; (C) the Late Carboniferous eugenodont Fadenia, × 0.16; (D) the Early Carboniferous xenacanthid Diplodoselache, × 0.08; (E) the xenacanthid Xenacanthus, × 0.08. Note the differences in cranial and vertebral ossification and fin structure (after Carroll, 1988).

Geological sketch map of southern Scotland and northern England with the positions of the Carboniferous GCR fish sites. Key to localities: A, Abden; B, Bearsden; CB, Cheese Bay; EK, East Kirkton; F, Foulden; G, Glencartholm; I, Inchkeith; R, Ardross Castle; W, Wardie.

Sketch map of the GCR site at Foulden.

Stratigraphical section at the Foulden site with the fish bed detailed (after Wood and Rolfe, 1985).

Foulden acanthodians: (A) Acanthodes ovensi White, with a series of immature forms showing the progressive spread of squamation forward during growth (from Forey and Young, 1985): (B) White's (1927) figure of the holotype (NHM P 13137) of A. ovensi.

Foulden sarcopterygians: (A) preliminary reconstruction of ?Strepsodus aulaconamensis sp. with scale cover; (B) ?Strepsodus aulaconamensis Andrews, with scales omitted to show lepidotrichia and axial skeleton (after S.M. Andrews, 1985) Many of the head and axial skeleton bones are largely conjectural. (C) Coelacanth flank scales (from Forey and Young, 1985).

Foulden actinopterygians (after White, 1927). (A) Aetheretmon valentiacum White; (B) Phanerosteon mirabile White; (C) Strepheoschema fouldenensis White.

Sketch map and geological section at the Wardie GCR site, East Lothian (after Wood, 1975).

Actinopterygians in nodules from the Wardie Shale, Wardie, (A)–(D) are all c. × 0.66. (A) Cosmoptychius striatus Agassiz, specimen in nodule; (B) Elonichthys robisoni Hibbert; (C) Rhadinichthys ferrox Traquair; (D) Nematoptychius greenocki Traquair; (E) Gonatodus punctatus Agassiz, restoration from Gardiner (1967a); (F) Nematoptychius greenocki Traquair, restoration of the head by Gardiner (1963), c. × 0.5.

Wardie elasmobranchs; (A) Diplodoselache woodi Dick, restoration of the skeleton, after Dick (1981); (B,a) scales from the anterior part of the trunk; (B,b) scales from the anal fin; (B,c) flank scales; (B,d) scales from head, body and tail; (C) Tristychius arcuatus Agassiz restoration of the skeleton (after Dick, 1978); (D) Onychoselache traquairi Dick, restoration (after Dick, 1978); (E) The Wardie tetrapod Lethiscus stocki Wellstead, a restoration of the dorsal surface of the skull (after Wellstead, 1982); (F) the Acanthodes sulcatus Agassiz restoration after Moy-Thomas and Miles (1971).

Sketch map of the Glencartholm GCR site, Berwickshire.

Some of the relatively more common Glencartholm actinopterygians: restorations in lateral view by Moy-Thomas and Bradley Dyne (1938). (A) Rhadinichthys fusiformis Traquair; (B) R. canobensis Tranquair; (C) Canobius ramsayi Traquair; (D) C. elegantulus Traquair.

Glencartholm actinopterygians: restorations in lateral view by Moy-Thomas and Bradley Dyne (1938). (A) Cycloptychius concentricus Traquair; (B) Mesopoma politum Traquair; (C) Mesopoma crassum Traquair.

Glencartholm actinopterygians: restorations in lateral view by Moy-Thomas and Bradley Dyne (1938). (A) Holurus parki Traquair; (B) the elongated Tarrasius problematicus Traquair, once thought to be a crossopterygian (after Moy-Thomas, 1937b); (C) Platysomus superbus Traquair; (D) Cheirodopsis geikiei Traquair. (C) and (D) are typical deep-bodied actinopterygians.

Glencartholm elasmobranchs. (A) Sphenacanthus costellatus Traquair, restoration (after Moy-Thomas, 1936); (B) Goodrichichthys eskdalensis, Moy-Thomas restoration; (C) Tristychius arcuatus Agassiz, isolated teeth; a, lingual; b, lateral; c, labial views of RSM 1972.276.461A; d, labial view of RSM 1972.27.460B.

Glencartholm holocephalians. (A) Chondrenchelys problematica Traquair in lateral restoration after Patterson (1965). (B) Deltoptychius armigerus Traquair, restoration of the headshield in dorsal view based on NHM P 11372 (after Patterson, 1966); anterior at top, incompletely fused tesserae make up the central part of the shield. (C) Dentition restored as if seen in front of wide-open mouth. (D) Deltoptychius, restoration of the fish courtesy of the Hunterian Museum, Glasgow; overall length of the specimen from Bearsden (q.v.) c. 60 cm.

Section of the Cheese Bay GCR site.

Sketch map of Inchkieth.

Ardross Castle site fossil actinopterygians: (A) Watsonichthys pectinatus Traquair, skull in lateral view (after Gardiner, 1963); (B) Rhadiniscus wrighti White, skull in lateral view; (C) the coelacanth Rhabdoderma, restoration in lateral view (after Forey, 1981).

Sketch map of the GCR site at Abden.

Steeplehouse Quarry elasmobranchs. Teeth of the hybodont selachian Lissodus wirksworthensis Duffin: (A) NHM P60741 in labial view; (B) P 60739 in occlusal view; (C) holotype P 60740 in occlusal view; (D) in lingual view; (E) labial view; (F) P 60752 in occlusal view; (G) labial view; (H) lingual view; (I) P 60748 in occlusal view; (J) labial view (after Duffin, 1985).

(A) Sketch map of the Bearsden area, Glasgow, with the stratigraphical section (B) found in the Manse Burn Formation (after Wood, 1982).

Bearsden actinopterygians: (A) Mesopoma carricki Coates in lateral restoration (after Coates, 1993); (B) Frederichthys musadentatus Coates, a composite restoration after the holotype GLAHM V 8286 (from Coates, 1993). Bearsden actinopterygians: (C) Melanecta annaea, GLAHM V 8255, × 2, photographed in UV light; (D) Mesopoma carricki, GLAHM V 8254, × 1.5, photographed in toluene; (E) Cheirodus sp., GLAHM, × 1.25 (Photos: courtesy of Hunterian Museum,, Glasgow).

Bearsden fishes: (A) the acanthodian Acanthodes sp., GLAHM unnumbered photo in toluene and figured as a restoration in lateral view; (B) Deltoptychius, GLAHM unnumbered photo in toluene at × 0.3; (C) Stethacanthus sp. (the ‘Bearsden Shark’) GLAHM V8246 at × 0.25 (Photos: courtesy of Hunterian Museum,, Glasgow). (D) reconstruction of the Stethacanthus skeleton (after Zangerl, 1981); (E) the Bearsden shark Stethacanthus sp., c. × 0.1.

Map showing the outcrop of Permian rocks in Great Britain, with the Middridge GCR site indicated (1).

Palaeogeographical map showing Britain during the early part of the English Zechstein Cycle 1 and equivalents, c. 255 Ma (after D.B. Smith, in Cope et al., 1992). Symbols indicate various invertebrate fossils.

Correlation of part of the Permian succession of northern England with that in North Germany and Holland (after Smith, 1989).

The Zechstein Sea, showing the major sub-basins and the land masses (after Smith, 1992). Sea depth was nowhere more than 30 m; the English Basin was less than 250 mm deep.

The palaeoniscid Palaeoniscus freieslebeni Blainville: (A) restored lateral view (after Aldinger, 1937); (B) reconstruction of the head (after Westoll, 1941).

(A) Dorypterus hoffmanni Germar, restoration in lateral view (after Westoll, 1941); (B) Platysomus striatus Agassiz (from King, 1850).

(A) the semionotid Acentrophorus restored in lateral view (after Gill, 1925), with specimens, (B), (C) from the Marl Slate, Middridge (natural size) (figured by King, 1850).

The holocephalian Janassa bituminosa (Schlotheim) in ventral view, and showing the petalodont dentition (after Shaumberg, 1978).

(A) Coelacanthus granulatus Agassiz, a restoration in lateral view (after Moy-Thomas and Westoll, 1935); (B) specimen from the Marl Slate, Middridge, figured by King (1850).

Wodnika striatula Munster, reconstruction by Schaumberg (1978).

Components of the fossil fish fauna from the German Kupferschiefer, probably closely comparable to that at Middridge. Palaeoniscids make up more than 90% of the assemblage, while the larger actinopterygians and the coelacanth constitute less than 5% at the top of the trophic pyramid (after Schaumberg, 1978).

Palaeogeography of Britain in late Triassic time (after Bradshaw et al., 1992). Connection with the Tethyan ocean lies via the east and south, with the Boreal ocean via the north.

British Triassic stratigraphy (after Warrington et al., 1980).

Map showing main outcrop of Triassic strata in England and Wales, with GCR sites at Sidmouth and Aust Cliff indicated.

The diversity of fishes in the Triassic and Jurassic periods (after McCune and Schaeffer, 1986). The width of each band at the middle of a division reflects the number of genera known from that division.

Map of coastal outcrop of the Otter Sandstone Formation between Sidmouth and Budleigh Salterton, South Devon (from Benton and Spencer, 1995).

View eastwards of Sidmouth cliffs, exposing the Otter Sandstone Formation in which fish and tetrapod remains occur at various levels (photo: M.J. Benton).

Otter Sandstone Formation fish: Dipteronotus cyphus Egerton.

Aust Cliff, north of the Aust Service Area: the pale band of the Penarth Group high in the cliff face contains lenses of Rhaetic Bone Bed (photo: G. W. Storrs).

The Rhaetian at Aust Cliff: (A) geological map; (B) stratigraphical section (both from Benton and Spencer, 1995, after Hamilton, 1977).

Fossils from the Rhaetic Bone Bed, Aust Cliff: (A) idealized characteristic tooth plate of Ceratodus latissimus Agassiz (c. 6 cm long) in occlusal aspect; (B), (C) Polyacrodus cloadcinus (Quenstedt), idealized tooth (c. 2.5 cm in antero-posterior length) in lingual and apical aspects; (D) Gyrolepis alberi Agassiz, idealized scale (c. 0.5 cm long; (E), (F) Nemacanthus monilifer Agassiz, reconstructed fin spine (c. 12 cm long) in transverse section and right lateral aspects; (G), (H) typical Lissodus minimus (Agassiz) tooth (c. 0.3 cm in antero-posterior length, in lingual and apical aspects; (I), (J) Severnichthys acuminatus (Agassiz) neotype, dentary, BRSMG 7976 (c. 10.5 cm long) in left lateral aspect and medial aspect; (K) fin spine of the rare Palaeospinax rhaeticus Duffin (c. 7 cm long). (All figures from Storrs, 1994.)